With eyes on the new glazed pavilion designed by Renzo Piano Building Workshop, here's a look back at Louis Kahn's original Kimbell, which put the institution on the architectural map.

When photographer Richard Barnes was in Fort Worth, Texas, documenting the new Renzo Piano Pavilion at the Kimbell Art Museum (designed, appropriately, by Renzo Piano, Hon. FAIA), he also documented the beloved 1972 masterwork designed by Louis Kahn that gave the arts institution its architectural pedigree. Here are some of those photos of what Kahn's Kimbell looks like 41 years on, supplemented with some of Kahn's original sketches, and archival photos from the design and construction process of the iconic structure.

The main entrance, with its grove of trees. View from the west.

Credit: Richard Barnes

View southwest toward the new Renzo Piano Pavilion from under the colonnade of the Kahn building.

Credit: Richard Barnes

Kahn's 1972 building for the Kimbell Art Museum. View from the southwest.

Credit: Richard Barnes

Double staircase, leading from oft-used east entrance up to the galley levels on the main floor.

Credit: Richard Barnes

Gallery, with daylit vaults.

Credit: Richard Barnes

View through to several vaulted galleries in the Kahn building.

Credit: Richard Barnes

Paintings hung on the travertine gallery walls.

Credit: Richard Barnes

View of the café.

Credit: Richard Barnes

Theater in the original Kahn building (in this case showing a film of Renzo Piano describing the new pavilion).